Objectives and methods: 1. To define the role of heme in the synthesis of globin and of other proteins in erythroid and non-erythroid cells (1) by the study of the effect of added hemin on the progressive steps in the formation of the initiation complex in globin synthesis, (b) by study of the synthesis of alpha and beta chains of globin cell- free systems in which the regulatory effects of mRNA and initiation factors can be defined, and (c) by study of the effect of hemin on the synthesis of proteins in non-erythroid eukaryotic and prokaryotic cells. 2. To define the chemical composition of the chromatin activated to transcribe the genes for globin by study of the induction of hemoglobin synthesis and differentiation in leukemia virus-transformed cells, fractionation of the chromatin, localization of the globin genes and analysis of the chemical changes in the activated chromatin. 3. To develop techniques for the localization of globin mRNAs and globin genes in cytologic preparations. 4. To study the factors which enhance or inhibit the polymerization of dioxyhemoglobin S by a new method of light scattering spectroscopy.